Gripper bar mechanism



2, 1952 A. J. ALBRECHT 2,

GRIPPER BAR MECHANISM Filed March 26, 1947 AJaxqnder J AJbrE/abzINVENTOR Patented Dec. 2, 1952 UNITED STATES PATENT OFFICE GRIPPER BARMEOHAN ISM Alexander J. Albrecht, West New York, N. J., as-

signor to R. Hoe & 00., Inc., New York, N. Y., a corporation of New YorkApplication March 26, 1947, Serial No. 737,236

6 Claims.

This invention relates to printing machines and more particularly tosheet fed machines of the flexible conveyor type.

A sheet fed printing machine of the flexible conveyor type, and to whichthe present improvements may be applied, is fully described in HuckPatent 2,231,914.. As there disclosed, the successive sheets are carriedthrough the printing uni-ts by gripper bars having a number of gripperelements or jaws which open and close to receive a sheet at theregistering unit anddischarge a sheet at the delivery, but which remainclosed during the passage of the sheetthrough the'successive printingunits.

One object of the present invention is to provide an improved gripperbar and mechanism for opening and closing the gripper elements thereof.v

A further object ofthe invention is to provide an improved device forholding a sheet adjacent its corners. Y

. With these and still 'other objects which will appear in the followingfull description in mind, the invention consists in the combinations andarrangements of parts and details of construction which will now firstbe fully described in connection with the accompanying drawing. and thenbe more particularly pointed out in the appended claims.

In the drawing: I

Figure 1 is a crosssection througha gripper barand parts of aregistering cylinder;

Figure 2 is a plan view of one. end of the gripper bar of Fi ure 1;' V

Figure 3 is a plan view on a reduced scale of one end of the gripper barand registering cylinder;

Figure 4 is a detail view showing an attachment employed for holdingdown a sheet corner; and

Figure '5 is a section on the line 55 of Figure 4.

The invention relates to the gripper bar and the mechanism employed foropening and closing the jaws thereof. The other press elements and theiroperation and cooperation with th gripper bar are well known inthemselves, being fully described in the Huck patent above referredtoand, accordingly, are not shown herein.

Figure 1 shows a portion of a registering cylin.--

der l having a recess 2 in which the gripper bar 3 is received. As willbe well understood by those skilled. in the art, the gripper bar will beseated in the recess 2 at a proper point in the rotation of theregistering cylinder and. the mechanism within and associated with thecylinder will operate to open and close the jaws of the gripper forreceiving and grasping a registered sheet. Heretofore, and as shown inthe Huck patent, the gripper bars have comprised a plurality-of elementsextending longitudinally of the registering cylinder and to which arelative movement is imparted for the purpose of controlling the actionof gripper jaws associated therewith. Such elements have taken the formof telescoped tubes, one jaw of each gripper being carried by an outertube, and the other by the inner tube, so that relative movement ofthese tubes causes the jaws to open and close. Such a construction isrela-. tively heavy, complicated and bulky and theaction of theregistering cylinder upon ths ripper bar may have a tendency to unseatthe gripper 'bar.

The gripper bar of the present invention com-1 prises a singlelongitudinally extending element in the form of a tube 4 which carriesanumber of gripper elements 5 spaced along its lengthat suitableintervals. Each gripper element 5 comprises a frame 6 which is fastenedto the tube 4 as by means of thescrews 1 and upon which is form-ed aninneror; lower jaw 80f a pair; of gripper jaws. The outer or upper jaw 9cooperating therewith. is carried by a lever 10 which is slotted asindicated to fit around the frame 6 and pivotally mounted thereon by ashaft H. the lever l0 counterclockwise about shaft ll separates or opensthe jaws 8 and 9, while swinging it clockwise into the position of thefigure causes the jaws to close for grasping a sheet. The lever in isoperated by a poppet bar I 2, one end of which is connected to the inneror lower end of the lever It by a link l3, having forks at each endwhich. are pivotally connected to the rod l2 and lever l0. and [5 foraccommodating the poppet rod [-2 and associated elements. The aperturel4 receives a thrust member I6 which surrounds the rod [2 and withinwhich the rod [2 slides, while the aperture. i5 is threaded and receivesa corre spondingly threaded thrust member l-T, also hav- Swinging Thetube 4 has opposed apertures Mling a central aperture through which therod I2 slides. A washer I8 is fastened to the rod I2 and inner and outersprings I9 and are interposed between the washer I8 and thrust membe IS.The spring pressure holds the thrust member I6 in the position shown, inwhich a, peripheral fiange thereon seats in a counterbore in the innersurface of the tube 4, as indicated, tending to force the washer I8against the fixed thrust member IT. A sheet of paper between the jaws 8and 9 will be held firmly thereby due to the action of the springs I9and 20 and washer I8 will be slightly spaced from the thrust member I!under such conditions. As will be apparent, a definite gripper pressureis thus obtained by each gripper 5, and this pressure will not beinfluenced by the action of any of the other grippers 5.

The gripper bar is located in a definite position in the registeringcylinder by rollers ZI rotatably mounted on a plate 22 fastened to theregistering cylinder and cooperating with bearer rings 23 toward theends of the gripper bar. At each end of the gripper bar there isfastened an end frame assembly 24 carrying a roller 25 which cooperateswith an upper cam track, the surface of which is indicated by thephantom line 26, for holding the gripper bar firmly down against therollers 2 I. The end frame assemblies 24 carry also rollers 2'! and 28for positioning the gripper bar in cylinder I, in the manner shown inthe Huck patent. A flexible conveyor in the form of a sprocket chain 29at each end of the gripper bar serves to carry the bar to and from thevarious units in the usual way.

The various grippers 5 are operated by a series of fingers 36 carried bya shaft 3|, which is journaled in the registering cylinder I and one endof which carries an arm 32 and cam follower roller 33, indicated inphantom in Figure l, the roller 33 following a stationary cam 34 afiixedto the frame and a portion of which is also indicated in Figure l. Thesolid line position of the fingers 38 in the drawing of Figure l is anintermediate position in which the fingers are just engaging the poppetrods I2 for opening the jaws 8 and 9. A box cam 3 is designed to movethe fingers 39 into a more outward position indicated by the phantomline 3% for providing space for the insertion and removal of the gripperbar and into a more inward position, indicated by the phantom outline 38for pressing the poppet rods I2 to open the gripper jaws. The operationof the cam and the control of the times of opening and closing of thegripper bar jaws may be the same as in the Huck patent referred to.

With the sheets of certain sizes it may happen that a sheet, when inlaterally registered position, will extend sufficiently far beyond thelast gripper element of the series which engages its forward end so asto create a possibility of the free corner of the sheet turning upwardsand becoming bent so as to spoil the appearance of the sheet andinterfere with the printing action. For holding down such a free corner,there is provided an attachment in the form of an offset finger mountedon an extending end 35 of the shaft I I associated with the gripper inquestion. The finger 35 is held on shaft II by screw 3? and is coupledto the movable jaw 9 by means of a pin 38 so as to move therewith. Thefinger 35 will not grip the sheet but will hold its corner down on thecylinder.

It will be understood that while a shaft 3 I with its gripper operatingfingers 3e and cam roller 33 is herein shown only in connection with aregistering cylinder, such as the cylinder 13 of Patent 2,231,914, it isalso used on a discharge cylinder that passes the sheets to a deliverysuch as the transfer chain 29 of the machine shown in the patent. Inthat machine, each of the gripper bars, of which there are nineteen in afour-unit machine, is provided with gripper operating mechanism, whereaswith the improved gripper bar herein disclosed, gripper operatingmechanism is required only on the registering cylinder and on thedischarge cylinder.

What is claimed is:

1. In a sheet fed printing press of the type having a plurality ofgripper bars carried through the press by conveyor chains, and incombination, a gripper bar comprising a tubular supporting member havinga plurality of aligned transverse bores spaced along its length, a fixedgripper jaw and movable gripper jaw adjacent each said bore, and anoperating rod slidably mounted in each bore, connected at one end to theadjacent movable jaw and spring pressed to hold the same in sheetgripping position against the fixed jaw, the opposite ends of the saidoperating rods extend ing outwardly from the said tubular supportingmember for pressing said rods inwardly against the action of the springsto open the gripper jaws, and a registering cylinder having means forreceiving and holding the gripper bar through a predetermined angle ofrotation of the cylinder, and a member mounted in the registeringcylinder and movable with respect to it for'pressing the said rods ofthe gripper bar, when so held, inwardly to open the gripperjaws.

2. In a sheet fed printing machine, and in combination, a plurality ofgrippers for receiving and holding the leading edge of a sheet andcomprising lower jaws and cooperating upper jaws movable with respectthereto for gripping and releasing a sheet, and means'operable with saidgrippers and located beyond the grippers for holding down the corner ofa sheet, the mechanism being constructed and arranged to provide a spaceunder the corner of the sheet when held down by the last said means.

3. In a sheet fed printing machine, a gripper bar comprising asupporting member and a plurality of grippers spaced therealong, andmeans also carried by said gripper bar, located beyond said grippers andoperable with said grippers for holding down the corner of a sheet upona registering cylinder, the gripper bar being constructed and arrangedso as to leave a space under the corners of the sheet when so held downby the last said means.

4. In a sheet fed printing machine, a gripper bar comprising asupporting member and a plurality of grippers spaced therealong, eachgripper comprising a fixed jaw and a movable jaw and means also carriedby said gripper bar beyond the grippers and movable with a movablegripper jaw for holding down the corner of a sheet upon a registeringcylinder, the gripper bar being constructed and arranged so as to leavea space under the corner of a sheet when so held down by the last saidmeans.

5. In a sheet fed printing machine, a gripper bar comprising asupporting member and a plurality of separately operable grippers spacedtherealong, and means also carried by said gripper bar beyond saidgrippers and operable with said grippers for holding down the corner ofa sheet upon a registering cylinder th grippers being constructed andarranged so as to 5 leave a space under a corner of a sheet when so helddown by the last said means.

6. In a sheet fed printing machine, a gripper bar comprising asupporting member and a plurality of separately operable grippers spacedtherealong, each gripper comprising a fixed inner jaw and movable outerjaw, and means also carried by said gripper bar beyond the grippers andoperable with the movable jaw of one of said grippers for holding downthe corner of a sheet upon a registering cylinder, the gripper bar beingconstructed and arranged so as to leave a space under the corner of asheet when so held down by the last said means.

ALEXANDER J. ALBRECHT.

6 REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 137,347 Cottrell Apr. 1, 1873747,213 Pancoast Dec. 15, 1903 1,050,842 Main Jan. 21, 1913 1,275,002Droitcour Aug. 6, 1918 1,495,257 Dudley May 27, 1924 1,508,951 BakerSept. 16, 1924 1,675,592 Blaine July 3, 1928 2,007,886 Stussi July 9,1935 2,231,914 Huck Feb. 18, 1941 2,392,392 Kaddeland Jan. 8, 19462,411,123 Wood Nov. 12, 1946

